Embedded System Expansion Driver Development

Nowadays, traffic police must carry with many types of equipment. This program aims at an integrate traffic system. In this system, the police need only a PDA.In this PDA, the CPU is used LH7A404 made by the company of SHARP. The operation system is the Linux operation system and GUI is based on QT. This article mainly introduces how to design the programs based on the Linux kernel. FPS200 fingerprint equipment driver, MC35 multiplex-plex device and keyboard driver are introduced.The FPS200 fingerprint equipment driver is introduced how to dezign FPS200 device in a Linux char driver. The MC35 multiplex program implements the MC35 multiplex protocol based on GSM07.10 agreement. The MC35 multiplex protocol mainly introduces how to let MC35 support the basic GSM07.10 multiplex pattern. The MC35 multiplex protocol procedures are composed of three parts which are virtual serial port driver, the dummy virtual serial port driver, and multiplex daemon. The virture serial port driver implements a driver which lets upper program for example SMS look like to operate its real actual serial port. The dummy serial port driver is a char driver which can read the data from virtual port. The mutiplex daemon is a progam in user level. On the one hand, it writes the data from dummy virtual seral port to the actual port. On the other hand it writes the data from actual port to the dummy virtual port. The pressed-key driver lets the pressed-key designed by users become the the stardard Linux terminal device.